Conventionally, as described in Patent Document 1 (JP H10-038605A), a vehicle maintenance period informing device has been known and includes an arrangement which accumulates traveling distance of a vehicle and provides information at every predetermined accumulated traveling distance that oil replacement is recommended.
In such method of providing information at every predetermined accumulated traveling distance that oil replacement is recommended, usually, a predetermined accumulated traveling distance is determined based on a normal operating state, and information is provided that oil replacement is recommended every time when the predetermined accumulated traveling distance is reached.